Sean Kingston expected to fully recover, sources say

NEW: The singer suffered a broken jaw, fractured wrist, water in his lungs, sources say

NEW:Fellow recording artist Trav visits, says he's "very responsive"

(CNN) -- Sean Kingston's injuries from a Miami jet ski crash should be healed in about six weeks, two sources close to the hip-hop artist told CNN Tuesday.

Kingston, 21, suffered a broken jaw, fractured wrist and water in his lungs, according to the sources, who both asked not to be identified since they were not authorized to speak to the media.

A publicist for Epic Records, which distributes his music, issued a statement Tuesday morning saying Kingston was in "critical but stable condition" in the intensive care unit of a Miami hospital.

Cassandra Sanchez, 23, was riding on the Sea Doo jet ski with Kingston when it crashed into a Miami bridge Sunday night, according to an accident report from the Florida Fish and Wildlife Conservation Commission. Sanchez was also injured and hospitalized.

Kingston had just bought the jet ski days before, as he was moving into a new house in Miami, one of the sources said.

His life vest apparently fell off during the crash, causing Kingston to sink below the water, according to witnesses.

"They were calling us over, telling us, 'He's drowning, he's drowning,' " said Carmen Rivera, who was boating nearby with her husband Jonathan Rivera and friend Jimmy Vega. The three rescuers were interviewed by CNN affiliate WSVN-TV.

"We jumped in the water to help him keep his head above water," Vega said.

"I pushed him up, and he was vomiting what seemed like water, and then there was some blood coming out," Jonathan Rivera said.

Recording artist Trav, who visited Kingston at the hospital Monday, told CNN he was "very responsive."

Trav's newest song "Up and Down," which releases Wednesday, features Kingston.

The Miami-born artist changed his name from Kisean Anderson to Kingston to reflect his Jamaican heritage.

He shot to fame in 2007 when his debut song "Beautiful Girls" became a No. 1 hit in the United States.